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Hong YB, Park JM, Yu JS, Yoo DH, Nam DE, Park HJ, Lee JS, Hwang SH, Chung KW, Choi BO. Clinical characterization and genetic analysis of Korean patients with X-linked Charcot-Marie-Tooth disease type 1. J Peripher Nerv Syst 2017; 22:172-181. [PMID: 28448691 DOI: 10.1111/jns.12217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/17/2017] [Accepted: 04/17/2017] [Indexed: 11/30/2022]
Abstract
Mutations in the gap junction protein beta 1 gene (GJB1) cause X-linked Charcot-Marie-Tooth disease type 1 (CMTX1). CMTX1 is representative of the intermediate type of CMT, having both demyelinating and axonal neuropathic features. We analyzed the clinical and genetic characterization of 128 patients with CMTX1 from 63 unrelated families. Genetic analysis revealed a total of 43 mutations including 6 novel mutations. Ten mutations were found from two or more unrelated families. p.V95M was most frequently observed. The frequency of CMTX1 was 9.6% of total Korean CMT family and was 14.8% when calculated within genetically identified cases. Among 67 male and 61 female patients, 22 females were asymptomatic. A high-arched foot, ataxia, and tremor were observed in 87%, 41%, and 35% of the patients, respectively. In the male patients, functional disability scale, CMT neuropathy score, and compound muscle action potential of the median/ulnar nerves were more severely affected than in the female patients. This study provides a comprehensive summary of the clinical features and spectrum of GJB1 gene mutations in Korean CMTX1 patients.
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Affiliation(s)
- Young B Hong
- Stem Cell & Regenerative Medicine Institute, Samsung Medical Center, Seoul, Korea
| | - Jin-Mo Park
- Department of Neurology, College of Medicine, Dongguk University, Gyeongju, Korea
| | - Jin S Yu
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Da H Yoo
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Da E Nam
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Hyung J Park
- Department of Neurology, Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea
| | - Ji-Su Lee
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Sun H Hwang
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Ki W Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
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Nam SH, Hong YB, Hyun YS, Nam DE, Kwak G, Hwang SH, Choi BO, Chung KW. Identification of Genetic Causes of Inherited Peripheral Neuropathies by Targeted Gene Panel Sequencing. Mol Cells 2016; 39:382-8. [PMID: 27025386 PMCID: PMC4870185 DOI: 10.14348/molcells.2016.2288] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/11/2016] [Accepted: 02/22/2016] [Indexed: 12/19/2022] Open
Abstract
Inherited peripheral neuropathies (IPN), which are a group of clinically and genetically heterogeneous peripheral nerve disorders including Charcot-Marie-Tooth disease (CMT), exhibit progressive degeneration of muscles in the extremities and loss of sensory function. Over 70 genes have been reported as genetic causatives and the number is still growing. We prepared a targeted gene panel for IPN diagnosis based on next generation sequencing (NGS). The gene panel was designed to detect mutations in 73 genes reported to be genetic causes of IPN or related peripheral neuropathies, and to detect duplication of the chromosome 17p12 region, the major genetic cause of CMT1A. We applied the gene panel to 115 samples from 63 non-CMT1A families, and isolated 15 pathogenic or likely-pathogenic mutations in eight genes from 25 patients (17 families). Of them, eight mutations were unreported variants. Of particular interest, this study revealed several very rare mutations in the SPTLC2, DCTN1, and MARS genes. In addition, the effectiveness of the detection of CMT1A was confirmed by comparing five 17p12-nonduplicated controls and 15 CMT1A cases. In conclusion, we developed a gene panel for one step genetic diagnosis of IPN. It seems that its time- and cost-effectiveness are superior to previous tiered-genetic diagnosis algorithms, and it could be applied as a genetic diagnostic system for inherited peripheral neuropathies.
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Affiliation(s)
- Soo Hyun Nam
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Young Bin Hong
- Stem Cell & Regenerative Medicine Center and Neuroscience Center, Samsung Medical Center, Seoul 06351,
Korea
| | - Young Se Hyun
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Da Eun Nam
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
| | - Geon Kwak
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Tech., Sungkyunkwan University, Seoul 06351,
Korea
| | - Sun Hee Hwang
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicine Center and Neuroscience Center, Samsung Medical Center, Seoul 06351,
Korea
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul 06351,
Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science & Tech., Sungkyunkwan University, Seoul 06351,
Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju 32588,
Korea
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3
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Bucci C, Bakke O, Progida C. Charcot-Marie-Tooth disease and intracellular traffic. Prog Neurobiol 2012; 99:191-225. [PMID: 22465036 PMCID: PMC3514635 DOI: 10.1016/j.pneurobio.2012.03.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 12/23/2011] [Accepted: 03/13/2012] [Indexed: 12/23/2022]
Abstract
Mutations of genes whose primary function is the regulation of membrane traffic are increasingly being identified as the underlying causes of various important human disorders. Intriguingly, mutations in ubiquitously expressed membrane traffic genes often lead to cell type- or organ-specific disorders. This is particularly true for neuronal diseases, identifying the nervous system as the most sensitive tissue to alterations of membrane traffic. Charcot-Marie-Tooth (CMT) disease is one of the most common inherited peripheral neuropathies. It is also known as hereditary motor and sensory neuropathy (HMSN), which comprises a group of disorders specifically affecting peripheral nerves. This peripheral neuropathy, highly heterogeneous both clinically and genetically, is characterized by a slowly progressive degeneration of the muscle of the foot, lower leg, hand and forearm, accompanied by sensory loss in the toes, fingers and limbs. More than 30 genes have been identified as targets of mutations that cause CMT neuropathy. A number of these genes encode proteins directly or indirectly involved in the regulation of intracellular traffic. Indeed, the list of genes linked to CMT disease includes genes important for vesicle formation, phosphoinositide metabolism, lysosomal degradation, mitochondrial fission and fusion, and also genes encoding endosomal and cytoskeletal proteins. This review focuses on the link between intracellular transport and CMT disease, highlighting the molecular mechanisms that underlie the different forms of this peripheral neuropathy and discussing the pathophysiological impact of membrane transport genetic defects as well as possible future ways to counteract these defects.
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Affiliation(s)
- Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Via Provinciale Monteroni, 73100 Lecce, Italy.
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Mandich P, Grandis M, Geroldi A, Acquaviva M, Varese A, Gulli R, Ciotti P, Bellone E. Gap junction beta 1 (GJB1) gene mutations in Italian patients with X-linked Charcot-Marie-Tooth disease. J Hum Genet 2008; 53:529-533. [PMID: 18379723 DOI: 10.1007/s10038-008-0280-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 03/05/2008] [Indexed: 12/15/2022]
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X) is a peripheral neuropathy transmitted in a dominant manner and caused by mutations in the Connexin 32 (Cx32) gene (GJB1, gap junction beta 1). Here we report the mutation analysis of the GJB1 gene in 76 subjects with possible CMT1 and absence of 17p11.2 duplication, and in 38 CMT2 patients without mutations in CMT2-associated-genes, selected from a cohort of 684 patients with peripheral sensory-motor neuropathy. The analysis was performed by direct sequencing of the coding sequence and exon/intron boundaries of the GJB1 gene. The mutation screening identified 22 mutations in GJB1, eight of which have not been previously published: six point mutations (c.50C > G, c.107T > A, c.545C > T, c.545C > G, c.548G > C, c.791G > T) and two deletions (c.84delC, c.573_581delCGTCTTCAT). The GJB1 mutation frequency (19.3%) and the clinical heterogeneity of our patients suggest searching for GJB1 mutations in all CMT cases without the 17p11.2 duplication, regardless of the gender of the proband, as well as in CMT2 patients with possible X-linked inheritance.
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Affiliation(s)
- Paola Mandich
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy.
| | - Marina Grandis
- Department of Neuroscience, Ophthalmology and Genetics, Section of Neurology and Neurological Rehabilitation, University of Genova, Genova, Italy
| | - Alessandro Geroldi
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
| | - Massimo Acquaviva
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
| | - Alessandra Varese
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
| | - Rossella Gulli
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
| | - Paola Ciotti
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
| | - Emilia Bellone
- Department of Neuroscience, Ophthalmology and Genetics, Section of Medical Genetics, University of Genova, c/o DIMI, Viale Benedetto XV, 6, 16132, Genova, Italy
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Casasnovas C, Banchs I, Corral J, Martínez-Matos JA, Volpini V. Clinical and molecular analysis of X-linked Charcot-Marie-Tooth disease type 1 in Spanish population. Clin Genet 2006; 70:516-23. [PMID: 17100997 DOI: 10.1111/j.1399-0004.2006.00724.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
From 1995 to 2004, 979 families with hereditary peripheral neuropathy were referred to the Genetic Diagnosis Center. Using single-strand conformation analysis (SSCA), the connexin 32 gene was analysed in all the patients from 498 families with sporadic or dominant inheritance with no male-to-male transmission and absence of the 17p2 duplication or deletion. Affected males had pes cavus, distal leg weakness, muscular distal atrophy, areflexia and distal sensory loss. The 106 families in which SSCA revealed abnormal migration electrophoresis were directly sequenced. We found 34 families (59 patients) with mutations in connexin 32 gene. In electrophysiological studies, 58.8% families presented slow and 14.7% intermediate nerve conduction velocities. Molecular findings revealed that codon 164 (29.4 +/- 15.3%) and the second extracellular (EC2) domain (44.1 +/- 16.6%) were the most frequently affected codon and domain of the connexin 32. Six novel mutations, Leu39fs, Glu47Gly, His153fs, Cys179Tyr, Cys201Phe and Ser211fs, were found in our study.
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Affiliation(s)
- C Casasnovas
- Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge-IDIBELL, Feixa Llarga s/n, L'Hospitalet de Llobregat, Barcelona, Spain.
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Mostacciuolo ML, Righetti E, Zortea M, Bosello V, Schiavon F, Vallo L, Merlini L, Siciliano G, Fabrizi GM, Rizzuto N, Milani M, Baratta S, Taroni F. Charcot-Marie-Tooth disease type I and related demyelinating neuropathies: Mutation analysis in a large cohort of Italian families. Hum Mutat 2001; 18:32-41. [PMID: 11438991 DOI: 10.1002/humu.1147] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Charcot-Marie-Tooth neuropathy type 1 (CMT1), the most common hereditary neurological disorder in humans, is characterized by clinical and genetic heterogeneity. It is caused mainly by a 1.5 Mb duplication in 17p11.2, but also by mutations in the myelin genes PMP22 (peripheral myelin protein 22), MPZ (myelin protein zero), Cx32 (connexin 32; also called GJB1), and EGR2 (early growth response 2). In this study, we have screened 172 index cases of Italian families in which there was at least one subject with a CMT1 diagnosis for the duplication on 17p11.2 and mutations in these genes. Among 170 informative unrelated patients, the overall duplication frequency was 57.6%. A difference could be observed between the duplication frequency in familial cases (71.6%) and that observed in non-familial cases (36.8%). Among the non-duplicated patients, 12 were mutated in Cx32, four in MPZ, two in PMP22, and none in the EGR2. In the non-duplicated cases, the overall point mutation frequency for these genes was 25.0%. We describe the mutations identified, and consider possible genotype-phenotype correlation.
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Affiliation(s)
- M L Mostacciuolo
- Laboratorio di Genetica Umana, Dipartimento di Biologia, Università di Padova, Padova, Italy.
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Tabaraud F, Lagrange E, Sindou P, Vandenberghe A, Levy N, Vallat JM. Demyelinating X-linked Charcot-Marie-Tooth disease: unusual electrophysiological findings. Muscle Nerve 1999; 22:1442-7. [PMID: 10487913 DOI: 10.1002/(sici)1097-4598(199910)22:10<1442::aid-mus16>3.0.co;2-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
X-linked Charcot-Marie-Tooth disease (CMT-X) is caused by mutations of connexin-32 (Cx-32), which encodes a gap-junction protein. Whether the neuropathy is primarily demyelinative or axonal remains to be established. We report findings of prominent demyelination in a 71-year-old woman with late-onset disease. Electrophysiological studies revealed a nonuniform slowing of motor conduction velocities and dispersion of compound action potentials indicative of a demyelinating process which was confirmed by nerve biopsy. Such electrophysiological features are unusual in hereditary neuropathies and are more commonly found with acquired chronic demyelinating neuropathies. A systematic search confirmed the molecular genomic diagnosis of CMT-X, illustrating the value of such tests in sporadic cases. Severity of clinical symptoms and signs may vary with age and sex of the patient. The pathology of CMT-X in other reported cases has been variably interpreted as axonal, demyelinating, or showing both features. Our observations emphasize the demyelinative nature.
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Affiliation(s)
- F Tabaraud
- Department of Neurology, University Hospital, 87042 Limoges, France
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Nelis E, Haites N, Van Broeckhoven C. Mutations in the peripheral myelin genes and associated genes in inherited peripheral neuropathies. Hum Mutat 1999; 13:11-28. [PMID: 9888385 DOI: 10.1002/(sici)1098-1004(1999)13:1<11::aid-humu2>3.0.co;2-a] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The peripheral myelin protein 22 gene (PMP22), the myelin protein zero gene (MPZ, P0), and the connexin 32 gene (Cx32, GJB1) code for membrane proteins expressed in Schwann cells of the peripheral nervous system (PNS). The early growth response 2 gene (EGR2) encodes a transcription factor that may control myelination in the PNS. Mutations in the respective genes, located on human chromosomes 17p11.2, 1q22-q23, Xq13.1, and 10q21.1-q22.1, are associated with several inherited peripheral neuropathies. To date, a genetic defect in one of these genes has been identified in over 1,000 unrelated patients manifesting a wide range of phenotypes, i.e., Charcot-Marie-Tooth disease type 1 (CMT1) and type 2 (CMT2), Dejerine-Sottas syndrome (DSS), hereditary neuropathy with liability to pressure palsies (HNPP), and congenital hypomyelination (CH). This large number of genetically defined patients provides an exceptional opportunity to examine the correlation between phenotype and genotype.
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Affiliation(s)
- E Nelis
- Flanders Interuniversity Institute for Biotechnology (VIB), Born-Bunge Foundation, University of Antwerp, Department of Biochemistry, Belgium
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Haites NE, Nelis E, Van Broeckhoven C. 3rd workshop of the European CMT consortium: 54th ENMC International Workshop on genotype/phenotype correlations in Charcot-Marie-Tooth type 1 and hereditary neuropathy with liability to pressure palsies 28-30 November 1997, Naarden, The Netherlands. Neuromuscul Disord 1998; 8:591-603. [PMID: 10093067 DOI: 10.1016/s0960-8966(98)00067-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bone LJ, Deschênes SM, Balice-Gordon RJ, Fischbeck KH, Scherer SS. Connexin32 and X-linked Charcot-Marie-Tooth disease. Neurobiol Dis 1997; 4:221-30. [PMID: 9361298 DOI: 10.1006/nbdi.1997.0152] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mutations in the gap junction gene connexin32 (Cx32) cause the X-linked form of Charcot-Marie-Tooth disease, an inherited demyelinating neuropathy. More than 130 different mutations have been described, affecting all portions of the Cx32 protein. In transfected cells, the mutant Cx32 proteins encoded by some Cx32 mutations fall to reach the cell surface; other mutant proteins reach the cell surface, but only one of these forms functional gap junctions. In peripheral nerve, Cx32 is localized to incisures and paranodes, regions of noncompact myelin within the myelin sheath. This localization suggests that Cx32 forms "reflexive" gap junctions that allow ions and small molecules to diffuse directly across the myelin sheath, which is a thousandfold shorter distance than the circumferential pathway through the Schwann cell cytoplasm. Cx32 mutations may interrupt this shorter pathway or have other toxic effects, thereby injuring myelinating Schwann cells and their axons.
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Affiliation(s)
- L J Bone
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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Rouger H, LeGuern E, Birouk N, Gouider R, Tardieu S, Plassart E, Gugenheim M, Vallat JM, Louboutin JP, Bouche P, Agid Y, Brice A. Charcot-Marie-Tooth disease with intermediate motor nerve conduction velocities: characterization of 14 Cx32 mutations in 35 families. Hum Mutat 1997; 10:443-52. [PMID: 9401007 DOI: 10.1002/(sici)1098-1004(1997)10:6<443::aid-humu5>3.0.co;2-e] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Charcot-Marie-Tooth disease can be inherited either autosomal dominantly or recessively or linked to the X chromosome. X-linked dominant Charcot-Marie-Tooth disease (CMTX) is a sensorimotor peripheral neuropathy in which males have usually more severe clinical symptoms and decreased nerve conduction velocities than do females. CMTX is usually associated with mutations in exon 2 of the connexin 32 (Cx32) gene. DNA from 35 unrelated CMT patients, without the 17p11.2 duplication, but with median nerve conduction between 30 and 40 m/s, were tested for the presence of Cx32 mutations. The entire coding sequence of the Cx32 gene was explored using a rapid nonradioactive technique to detect single-strand conformation polymorphisms (SSCP) on large PCR fragments. Thirteen abnormal SSCP profiles were detected and characterized by sequencing. In addition, systematic sequencing of the entire Cx32 coding region in the remaining index cases revealed another mutation that was not detected by SSCP. A total of 14 mutations were found, five of which were not previously reported. These results demonstrate the high frequency (40%) of mutations in the coding region of the Cx32 gene in CMT patients with intermediate MNCV, without 17p11.2 duplications. Most of these mutations (93%) can be detected by SSCP.
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